I brush my hair in the shower when it's drenched in conditioner because it's much too difficult to brush when it's dry. Is that bad? I've been doing it for about a year now. Would using a wide-toothed comb help? Or will the hair still break?

I guess it would depend on the type of brush you use and how you actually brush your hair.
I don't think it would make much difference whether you used a brush or comb if you were ripping it through your hair, but if you're doing it gently and teasing the tangles out as you go and It's working for you I'd keep doing it.